1. Field of the Invention
The present invention relates generally to a monitoring pattern for a semiconductor device and, more particularly, to a composite pattern available to monitor a variety of defects in a semiconductor device.
2. Description of the Related Art
Semiconductor integrated circuit devices are fabricated through a great number of process steps. However, to determine the yield and/or effectiveness of certain processing steps, it is beneficial to monitor unfavorable defects that often occur in such processing. A specific monitoring pattern is widely used in the art to ascertain whether a given fabrication process (or series of process steps) is performed as expected or not, and to analyze defect problems that may occur in each such fabrication process (or series of process steps).
To identify and/or ascertain whether any individual defect of a variety of defects may be present or may have occurred, many monitoring patterns should be present or involved in the semiconductor device. This may be, however, restricted by the area of the device, or otherwise, an increase in the area of the device may be caused since such conventional monitoring patterns are generally separately formed and independently used for each defect. Furthermore, where there is no monitoring pattern, some defects may not be found while or directly after a corresponding process is completed. In addition, a certain defect related with some problems may not allow an effective analysis of problems.
FIG. 1 shows, in a cross-sectional view, one example of a defect that may occur in a particular fabrication process of a semiconductor device. Referring to FIG. 1, an active region 11 surrounded by an isolation region 12 is connected to an overlying metal line 13 through a contact 14.
As semiconductor devices advance in integration, the active region 11 becomes smaller and narrower. This may invite or result in a reduction in the margin for a process for forming the contact 14, and may often cause or result in the contact 14 being placed in a wrong location, e.g., toward the isolation region 12. So, as shown in FIG. 1, since the isolation region 12 may be formed from a material similar or identical to the dielectric material 17 in which the contact 14 is formed, the contact 14 may extend downward at one bottom edge to a well region 15. Unfortunately, this extended edge of the contact 14 will act as a current leakage path 16 between the metal line 13 and the well region 15.
Such metal-to-well leakage and abnormal contact formation may not be detected until after all subsequent processes are completed. Unfortunately, this may cause considerable loss of productivity. In addition, even though any metal-to-well leakage defect can be found after fabrication, it is difficult to analyze a cause of the leakage defect using conventional monitoring patterns. So, a need is felt in the art for a monitoring pattern available for monitoring and analyzing such defects.